Laura Marling, Camden Barfly, London

She's speaking loud and clear

Two years ago, Laura Marling was often pigeonholed as the inheritor of Lily Allen's or Kate Nash's style of kitchen-sink pop.

Now, playing an intimate gig to a packed-out Camden Barfly and with the release of her second album, I Speak Because I Can, the new-folk starlet has become quite possibly the nation's most promising singer-songwriter talent. The early indie-pop hype never quite rang true. Marling was never an Allen-esque character, singing ironic ditties in a mockney accent. Rather, she's always been a challenging antidote to indie-pop and has now become the jewel in the British folk scene's crown, one increasingly reminiscent of classic Joni Mitchell or Kate Bush.

Once so painfully shy she avoided eye contact at gigs, the Hampshire-born songwriter still displays an innocence and fragility on stage, but is now more assured, flicking her hair and joking easily with the buzzing north London crowd of new folkies and trendy hipsters lucky enough to snare tickets for this tiny performance.

Apologising for her lateness – no one seems to mind despite the venue's Hades-like temperature – Marling launches into a romp through "Devil's Spoke", the first track from her new album. Lifting notes from Dylan's "It's Alright, Ma (I'm Only Bleeding)" it's powerful and aggressive at times, backed by powerful drums, bass, cello and keyboards, illustrating how far Marling has come from lyrical newcomer to accomplished artist. "Hope in the Air" also from her new album, is classic Marling again – trance-like and poetic as she offers subtle melodies and delicate vocals in contrast with the belted tunes "Devil's Spoke" and "Rambling Man". Tracks from her new album dominate the set, which includes two totally new tracks ("Rest in Bed" and "My Dear Friends") presumably from her forthcoming third album, scheduled for release later this year. Her new album's first single, "Goodbye England (Covered in Snow)", a beautifully told tale of a winter walk with her father, is disappointing live though, as she momentarily reverts to her less assured self and looks to the floor.

Delivered in her fuller, stronger voice, "Ghosts", one of the few crowd-pleasers performed from her Mercury prize-nominated album, Alas I Cannot Swim, brings a big cheer, before the band step aside for a clutch of solo tracks.

It's easy to forget that Marling is barely out of her teens and a rookie error – forgetting the lyrics midway through "Failure" – could have been disastrous if not for her bashful charm keeping her fans on board. "I got as far as making up new lyrics there, that's bad. Anyway, you get the gist," she says cutting the track off abruptly. Her fans giggle with her, her humour infectious; her ever more assured vocals and gently plucked melodies addictive. She is forgiven and her sin forgotten. As the band step back on stage, Marling relaxes, and offers an angry stream of consciousness in "Alpha Shallows", the most intense song on her new record. Her voice husky and beguiling, more assured than her earlier teenage days, as she positively screams out her infectious verses, before intense bass comes to the fore.

My companion, a long-time Marling follower, seems to think she still has more to give and could have worked the crowd harder. He's right and Marling undoubtedly has more to offer in the years to come. But it's clear she's no pop flash-in-the-pan destined for daytime radio or sampling on mobile broadband television adverts and that's why her fans adore her. As she closes with the Nick Drake-esque "I Speak Because I Can", which in part tells the tales of Ulysses and Penelope, she leaves the crowd transfixed, half shouting for joy, half fighting back the tears.